Building panels provided with a mechanical locking system comprising a displaceable and resilient tongue cooperating with a tongue groove for vertical locking is known and disclosed in, e.g., WO2006/043893, WO2007/015669 and WO2009/066153. The tongue is a separate part and is made of, e.g., plastic and inserted in a displacement groove at an edge of a panel. The tongue is pushed into the displacement groove during an assembling of the panels when the panels are moved vertically with respect to each other, and springs back into the tongue groove of an adjacent panel when the panels have reached a locked position.
Although most of the description relates to floor panel, the description of techniques and problems thereof is applicable also for other applications, such as panels for other purposes, for example wall panels, ceiling panels, furniture, etc.
A drawback with the known locking system is that the tongue may spring back with a lower force than desired.
The above description of various known aspects is the applicant's characterization of such, and is not an admission that any of the above description is considered as prior art.